This project investigates the psychophysiological and neurobiological mechanisms involved in dissociation and the dissociative disorders. Alter personalities of patients with multiple personality disorder, control subjects simulating alter personalities and normal subjects with differing degrees of dissociation are studied with a variety of methodologies and technologies. Current research involves correlations between memory deficits induced by alcohol or drugs in normal individuals and their degree of dissociation on clinical measures. Data on heart rate changes with personality state switches in multiple personality subjects and simulating controls are being analyzed.